Revert r195317 (and r195333), "Teach ISel not to optimize 'optnone' functions."

It broke, at least, i686 target. It is reproducible with "llc -mtriple=i686-unknown".

FYI, it didn't appear to add either "-O0" or "-fast-isel".

llvm-svn: 195339

1 files changed, 1 insertions, 40 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index faca3ee823c..91cb125dc89 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -223,39 +223,6 @@ defaultListDAGScheduler("default", "Best scheduler for the target",
 
 namespace llvm {
   //===--------------------------------------------------------------------===//
-  /// \brief This struct is used by SelectionDAGISel to temporarily override
-  /// the optimization level on a per-function basis.
-  class OptLevelChanger {
-    SelectionDAGISel &IS;
-    CodeGenOpt::Level SavedOptLevel;
-
-  public:
-    OptLevelChanger(SelectionDAGISel &ISel,
-                    CodeGenOpt::Level NewOptLevel) : IS(ISel) {
-      SavedOptLevel = IS.OptLevel;
-      if (NewOptLevel == SavedOptLevel)
-        return;
-      IS.OptLevel = NewOptLevel;
-      IS.TM.setOptLevel(NewOptLevel);
-      DEBUG(dbgs() << "\nChanging optimization level for Function "
-            << IS.MF->getFunction()->getName() << "\n");
-      DEBUG(dbgs() << "\tBefore: -O" << SavedOptLevel
-            << " ; After: -O" << NewOptLevel << "\n");
-    }
-
-    ~OptLevelChanger() {
-      if (IS.OptLevel == SavedOptLevel)
-        return;
-      DEBUG(dbgs() << "\nRestoring optimization level for Function "
-            << IS.MF->getFunction()->getName() << "\n");
-      DEBUG(dbgs() << "\tBefore: -O" << IS.OptLevel
-            << " ; After: -O" << SavedOptLevel << "\n");
-      IS.OptLevel = SavedOptLevel;
-      IS.TM.setOptLevel(SavedOptLevel);
-    }
-  };
-
-  //===--------------------------------------------------------------------===//
   /// createDefaultScheduler - This creates an instruction scheduler appropriate
   /// for the target.
   ScheduleDAGSDNodes* createDefaultScheduler(SelectionDAGISel *IS,
@@ -403,12 +370,6 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
   ST.resetSubtargetFeatures(MF);
   TM.resetTargetOptions(MF);
 
-  // Reset OptLevel to None for optnone functions.
-  CodeGenOpt::Level NewOptLevel = OptLevel;
-  if (Fn.hasFnAttribute(Attribute::OptimizeNone))
-    NewOptLevel = CodeGenOpt::None;
-  OptLevelChanger OLC(*this, NewOptLevel);
-
   DEBUG(dbgs() << "\n\n\n=== " << Fn.getName() << "\n");
 
   SplitCriticalSideEffectEdges(const_cast<Function&>(Fn), this);
@@ -987,7 +948,7 @@ static void collectFailStats(const Instruction *I) {
 void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
   // Initialize the Fast-ISel state, if needed.
   FastISel *FastIS = 0;
-  if (TM.Options.EnableFastISel || Fn.hasFnAttribute(Attribute::OptimizeNone))
+  if (TM.Options.EnableFastISel)
     FastIS = getTargetLowering()->createFastISel(*FuncInfo, LibInfo);
 
   // Iterate over all basic blocks in the function.